In a prior-art lifting bridge of this type (DE 86,27,720 U 1), the lifting members consist of vertical threaded spindles, which are arranged laterally at a support rail and can be lowered into an engine space opening by rotary actuation of a winged nut. The support rail consists of a rectangular tube, over which a guide tube carrying a lifting device is pushed nonrotatably but axially displaceably in a positive-locking manner. The threaded spindles are each arranged laterally next to the support rail, so that an overturning moment, which is able to lift the lifting bridge as a whole out of its anchoring at the edges of the fender, is generated when a load is suspended at the lower ends of the threaded spindles. In addition, a very strong clamping action is generated by the overturning moment between the support rail and the guide tube, which makes it very difficult, if not impossible, for the lifting device to be axially displaced under load. Moreover, the threaded spindles, which are rigid per se, permit a movement of the loads attached to them only in the vertical direction and along the support rail; movement of the load at right angles thereto is not possible. The maximum working stroke is also limited. This prior-art lifting bridge therefore has only limited applications and is unsuitable, e.g., for the floating suspension of a V-type engine for removing or installing its transmission.
Another lifting device, which supports a load from below and is suspended in the lateral leaf spring assemblies of, e.g., a truck, has been known from DE 37,32,837 C2. This device has only one, centrally arranged, vertical threaded spindle, which is led through the support frame, with an upper support plate, on which a load can be placed from the top. Even though this lifting device permits the central supporting of the load, the point of support itself is determined essentially nondisplaceably in the center of the motor vehicle due to the three-part support frame, which can be displaced laterally only slightly.